1. Field of the Invention
The present invention is a self-aligning bearing assembly for engaging and supporting, while permitting the free rotation of, the end of a load bearing shaft. The present invention employs supporting cam rollers in parallel relationship to the axis of the end of the shaft, and maintains the parallel relationship despite variations in the load carried by the shaft. Means for facilitating the easy placement and removal of the shaft from the assembly are also preferably provided. The invention is especially useful in industries where large rolls of paper or metal sheet material is unwound from or wound onto a supporting shaft.
2. Description of the Prior Art
The prior art teaches various assemblies for engaging and supporting, while permitting the free rotation of, a load bearing shaft. Frequently, however, the load carried by the supported shaft is variable. For example, where the shaft supports a roll of paper which is being unwound, the load on the shaft is substantially greater at the beginning than at the end of the unwinding procedure. Of course, the greater the load on the shaft, the more the shaft deflects. Accordingly at the ends of its axis, the shaft deflects angularly from the normal, unloaded axis of the shaft. The amount of the angular deflection of the shaft is dependent on several factors, including the load on the shaft, the stiffness of the material of which the shaft is made, and the dimensions of the shaft and particularly the distance between the supports for the shaft. Thus, the angular deflection at the end of the shaft, where the bearing assemblies which support the shaft are often located, frequently varies.
It is desirable to maintain the bearing assemblies in a prescribed and aligned relationship to the end of the shaft. Where a plurality of cam rollers is used in the bearing assembly to support and engage the shaft end, it is desirable to maintain the surface of each cam roller in parallel relationship to the axis of the end of the shaft. Maintenance of such a parallel relationship is desirable so that the load delivered by the end of the shaft is evenly distributed along the surface of each of the cam rollers, thereby minimizing wear on both the shaft end and the cam rollers. Although it is possible to manually adjust the relationship between the shaft end and the supporting cam rollers, where the shaft end is subject to various angular deflections such manual adjustment is impractical or at least very time consuming. Accordingly, it is desirable to have a bearing assembly which automatically adjusts to properly align the cam rollers to the shaft end. In addition, it is also desirable that the bearing assembly be provided with means to facilitate quick and easy placement of the shaft end into, and removal from, the bearing assembly.
The bearing assembly must, of course, be able to withstand a variety of both static and dynamic loads. Where the bearing assembly is to include a self-alignment mechanism, that mechanism must also be of sufficient strength to withstand such loads. Additionally, it is desirable that the self-alignment mechanism have a minimum of moving parts and assemblies so that the reliability of such a mechanism will be maximized while the cost of its manufacture and maintenance are minimized.